Container closure device capable of dispensing metered amounts of liquid

ABSTRACT

The present invention relates to a closure device capable of dispensing a metered amount of liquid into a container during a closing action and capable of doing so during several closing actions. The closure device comprises a cap wall, a reservoir ( 5 ) capable of being filled with a liquid, a rigid plate ( 4 ) with one or more perforations ( 6 ) and a porous structure ( 8 ). The invention further relates to use of a closure device to extend the open shelf-life of spoilage sensitive container contents.

FIELD OF INVENTION

The present invention relates to a container closure device capable of dispensing metered amounts of liquid.

BACKGROUND OF THE INVENTION

A variety of packaging materials represented by devices such as stoppers, lid seals, seals, caps, lids, plugs and valves designed to close bottles, flask, jars, boxes, cans, barrels, tanks, tubs and other containers used to package and store food, dietary products and cosmetic products are commercially available. A container is generally defined as an assembly of materials designed to receive, contain and protect a good intended to be stored, transported and opened by the consumer.

A suitable container may contribute to the preservation of its contents by forming a physical barrier to for example, external germs and microbes, moisture and direct sun-light. The barrier afforded by the container is breached upon opening, whereupon the contents may be exposed to air, which may initiate and/or quicken spoilage. A suitable container closure device, such as a screw-on cap, allows the opening and re-closure of the container, such as a bottle or jar, limiting the exposure and possibly extending the open shelf-life. The open shelf-life is defined as the time during which the contents are considered safe to consume after opening the container for the first time. For example, many food products have a maximum ‘open’ shelf-life during which they are considered safe to use after the container is opened for the first time by the consumer.

A known method to extend the open shelf-life is to mix chemical preservatives directly into the food product during manufacture such as antioxidants and antimicrobial compounds. However, the presence of preservatives, especially non-natural preservatives in foods, is 30 disliked by consumers and is considered unhealthy. Furthermore, typically a relatively large amount of preservatives are mixed throughout the product since it is not known beforehand which parts of the contents may experience exposure (e.g. surface layer).

US 2008/0169217 discloses a closure device capable of releasing preservatives directly onto the surface of a product in a container (i.e. the contents) upon closing of the container. Most of the preservatives held by the closure device are released into the container during the first closing action of the container with the closure device.

The release of most of the preservatives during the first closing action is undesirable. It may lead to a high local concentration on the surface (i.e. top-layer) of the product, which in turn may result in an off-taste when food is sampled by the consumer. Furthermore, when the top-layer of the food product is consumed the level of preservatives remaining in the food product may drop below their effective concentration.

WO 01/68470 discloses a device capable of releasing a gaseous aromatic material during several successive opening actions of a container. The closure device comprises an expandable/contractible hollow, which fills with gas, evaporated from an impregnated body, when the device is in place on the container (i.e. container is closed). When the container is opened gaseous material is expelled from the hollow into the headspace of the container.

Said closure device does not enable dispensing of a metered amount of liquid material nor teaches how to dispense material during closure of a container.

When the container is opened and closed several times in a short time-span, it may not be desirable that a liquid dosage is dispensed each time. For example, in case of a mayonnaise jar it may be opened and closed several times during the course of a dinner, while only a small amount of product is taken out each time. Limiting the amount of dispensed material during successive opening and/or closing actions when performed in quick succession may prevent premature depletion of the material (i.e. before a significant part of the container contents are consumed). Furthermore, it may prevent a high local concentration of the dispensed material forming on the surface (i.e. top-layer) of the product, which in turn may result in an off-taste when food is sampled by the consumer.

After the closure device is in place (i.e. closing the container) and a metered amount of material, such as a liquid, is dispensed, uncontrolled dispensing of liquid in the cap (e.g. from a reservoir) by leakage and/or evaporation is undesirable. For example, when the time span between two successive opening/closing actions is long (e.g. a jar stored for a month in a cupboard before being re-opened), the liquid level in a reservoir may slowly deplete by uncontrolled leakage and/or evaporation which may limit the amount of successive metered dispensing actions.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a container closure device capable of dispensing a metered amount of liquid into a container during several successive closing actions.

It is a further object of the present invention to provide a container closure device capable of controlling the amount of liquid dispensed into a container during several successive closing and/or opening actions when performed in quick succession.

It is a further object of the invention to provide a container closure device capable of dispensing a metered amount of liquid and to subsequently allow at least part of the dispensed material to come into contact with the container contents in gaseous form.

It is a further object of the invention to provide a container closure device capable of limiting the amount of uncontrolled liquid loss due to leakage and/or evaporation when in closed position (i.e. when in place) on the container.

We have met these objectives by the closure device of the present invention, which is capable of dispensing a metered amount of a liquid into a container during several closing actions. The closure device comprises a cap wall, a reservoir capable of being filled with a liquid, a rigid plate with one or more perforations, and one or more channels leading from the perforations to a porous structure, wherein at least part of the channel is formed by a deformable and elastic material. Said material is arranged such that it is capable of closing the communicating channels when compressed, typically as result of a closing action.

When the closure device is not in place on a container (e.g. when the container is open) fluid may flow from the reservoir through the one or more perforations in the rigid plate via the connecting channels into the porous structure, for example by capillary force and/or gravity. By virtue of having a maximum saturation (i.e. a maximum volume of liquid capable of being held by the porous structure) a metered amount may accumulate in the porous structure.

When the closure device is placed onto the container the deformable and elastic structure forming part of the connecting (i.e. communicating) channel or channels is compressed and restricts or stops flow of liquid from the reservoir through the channels into the porous structure. Therefore, once the closure device is placed onto the container a metered amount of liquid is present in the porous structure and is in contact with the container interior (e.g. headspace). While the container is closed with the closure device, the liquid evaporates and/or drips from the porous structure into the (rest of the) container interior and may come into contact with the container contents, such as a food product. When the porous structure has released a metered amount of liquid through gravity (e.g. dripping) and/or evaporation, the closure device is re-set to dispense another metered amount of liquid into the porous structure upon a subsequent opening action. If the porous structure is not yet suitably de-saturated, such as when the closure device-container combination is opened/closed a second time in quick succession, the capability of the porous structure to accumulate more liquid from the reservoir upon opening is reduced. Therefore, the maximum amount of liquid dispensed into the container (via the porous structure) during several opening/ closing actions when performed in quick succession is controlled. Upon opening of the container, by virtue of the elasticity of the deformable structure, the restricted and/or closed channel(s) may re-attain their uncompressed shape and again allow unrestricted flow of liquid from the reservoir through the channel(s) into the porous structure. Thus, the closure device is capable of dispensing a metered amount of liquid into a container, capable of doing so at least a second time and capable of controlling the amount of liquid dispensed into the container when opened/closed in quick succession.

Accordingly in a first aspect the present invention relates to a container closure device capable of dispensing a metered amount of a liquid into a container, wherein said container cap comprises:

-   -   a cap wall,     -   a reservoir capable of being filled with liquid,     -   a porous structure,     -   a rigid plate positioned between said reservoir and said porous         structure,         -   wherein said plate comprises one or more perforations             communicating with said reservoir, and     -   one or more channels capable of communicating said perforation         with the porous structure,         -   wherein at least part of said channels is formed by a             deformable and elastic structure capable of limiting             communication through said channels upon deformation.

It was further found that a closure device according to the invention may suitably be filled with a preservative and used to extend the open shelf-life of spoilage sensitive content of the container. Upon each closing action of the container, at least for the first two closing actions with the closure device, the container interior and its contents may be treated with dispensed material, such as a preservative.

Accordingly in a second aspect the present invention relates to a method to extend the open shelf-life of spoilage sensitive contents (i.e. products) held by a container comprising the step of closing the container with a closure device according to the invention.

DETAILED DESCRIPTION

The closure device according to the present invention is intended to include any form of closure for a container, and preferably includes various kinds of caps such as screw-caps, push-on caps, composite caps having a retractable pouring spout and the like. Also the invention is applicable to any type of container, though containers having a mouth-like opening such as bottles and jars are preferred. Other types of containers such as drums, tubs or cans are also within the ambit of the present invention. Preferably the closure device is applied to containers comprising foods, but non-food spoilage sensitive products also fall within the ambit of the invention. Solid products, semi-solid, semi-liquid as well as liquid products are applicable to the utilisation of the present invention.

With ‘dispensed into the container’ is meant the transfer of liquid material from the reservoir through the one or more perforations of the rigid plate into the porous structure. When the closure device is not in place on the container (i.e. container is opened) the porous structure is provided with a metered amount of liquid, as the channel between reservoir and porous structure is open. When the closure device is in place on the container (i.e. container is closed) the container interior is exposed to the metered amount of liquid in the porous structure. The dispensed liquid in the porous structure distributes over the container contents as liquid (e.g. by dripping) and/or in gaseous form (e.g. by evaporation). The gaseous form of the dispensed material allows more efficient distribution of the dispensed material over the entire air-exposed surface of the container and its contents. Preferably at least part and more preferably the entire metered dispensed liquid distributes over the container interior in gaseous form.

Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which;

FIG. 1 is an axial cross section through a first embodiment of the invention in open position. A sub-section of FIG. 1 is enlarged for detail. The cross section is made along the line A-A′ as shown in FIG. 3. and FIG. 4;

FIG. 2 is an axial cross section through the first embodiment of FIG. 1 screwed onto the neck of a container and closing it. A sub-section of FIG. 2 is enlarged for detail. The cross section is made along the line A-A′ as shown in FIG. 3. and FIG. 4;

FIG. 3 is an end view of the first embodiment of the side facing the interior of the container in case the closure device is in place on the container. A sub-section of FIG. 3 is enlarged for detail;

FIG. 4 is an end view of the first embodiment as in FIG. 3, but wherein the porous structure and the deformable and elastic structure have been deleted for illustration purposes. A sub-section of FIG. 4 is enlarged for detail;

FIG. 5 is an axial cross section through a second embodiment of the invention in open position. A sub-section of FIG. 5 is enlarged for detail;

FIG. 6 is an axial cross section through the second embodiment of FIG. 5 screwed onto the neck of a container and closing it. A sub-section of FIG. 6 is enlarged for detail;

According to a first general preferred but non-exclusive embodiment of the closure device according to the invention the screw-cap according to FIG. 1 is characterized by its additive function, which consists of containing and dispensing a liquid; and exposing a product in the container to the dispensed liquid as drops (i.e. as a liquid) and/or as a gas (e.g. by evaporation). In another embodiment screw-cap may be a click-on closure or the like. FIG. 1 shows a closure device according to the invention and the container in opened configuration. The closure device is in the form of a cap and is fitted with an internal thread (1) enabling it to be screwed onto the neck of the container (2). The cap wall (3) comprises an internal cavity that comprises a rigid plate (4), a reservoir (5), a deformable and elastic structure (10) and a porous structure (8). The reservoir (5) comprises a sponge-like material and is arranged in a disk. The reservoir (5) may be filled with a liquid, for example a preservative. The rigid plate (4) comprises several perforations (6). Two perforations (6) are visible in the axial cross-section of the embodiment shown in FIG. 1. The closure device further comprises several channels (7) connecting to the perforations (6) and allowing communication of the reservoir (5) with the porous structure (8). In this particular embodiment of the closure device, the channels (7) tunnel through a ledge (9) which encircles the porous structure (8). The channels (7) are formed by the area enclosed by the rigid plate (4), the ledge (9) and the deformable and elastic structure (10). Thus part of the channels (7) (e.g. part of the channel wall) is made of the deformable and elastic structure (10). The deformable and elastic structure (10) can for example be made from silicon rubber. In this particular embodiment, the porous structure (8) is made of an absorbent sponge-like material capable of absorbing liquid. Liquid present in the reservoir (5) is capable of flowing through the perforations (6) via the channels (7) into the porous structure (8). In this particular embodiment, the porous structure (8) is capable of holding from 1 to 15 volume percent of the maximum amount of liquid which can be held by the reservoir (5).

FIG. 2 shows the cap according to FIG. 1. screwed onto the neck of the container thereby closing it. When the closure device is in place on the neck of the container, the deformable and elastic structure (10) is deformed, by the container mouth (11) having come into close proximity with the rigid plate (4), and closes the channels. Said closure stops the flow of liquid from the reservoir (5) to the porous structure (8) and also prevents further leakage and/or evaporation of liquid in the reservoir when the closure device is in place on the container. Dispensed liquid which may be present in the porous structure (8) may suitably evaporate and/or drip into the interior of the container.

FIG. 3 is a view of the closure device of the first embodiment, wherein the side is shown facing the interior of the container in case the closure device is in place on the container. The A-A′ dashed line represents the position of the axial cross-sections shown in FIG. 1 and FIG. 2. The parts of the channel (7) tunneling through the ledge (9) are illustrated by dotted lines, although said parts are (i.e. tunnels) typically not visible from this perspective. The closure device of the first embodiment comprises a deformable and elastic structure (10) which forms a circular flap around the porous structure (8) from which it is separated by a ledge (9).

FIG. 4 is a view of the closure device of the first embodiment, as FIG. 3, but wherein the porous structure (8) and the deformable and elastic structure (10) have been deleted from the illustration to show the perforations (6) and a larger part of the channel (7). Again, the parts of the channel tunneling (7) through the ledge (9) are illustrated by dotted lines. The closure device of the first embodiment comprises ten perforations (6) spaced radially around the porous structure (8) to enable liquid to flow from the reservoir (5) at multiple points. The number and radial arrangement of the perforations (6) shown in FIG. 3 is not essential. The shown arrangement is only illustrative of a specific embodiment and is non-limiting.

It will be appreciated that depending on the particular shape of the deformable and elastic structure (10) one or more channels (7) may be defined. In the particular embodiment illustrated in FIG. 1 to FIG. 4 the deformable and elastic structure (10) forms a circular flap and the enclosed area underneath it (i.e. channel (7)) forms a circular space which interconnects the perforations (6) and comprises the ten tunnels though ledge (9) leading off to the porous structure (8). Said enclosed space, including the ten tunnels may be seen as one channel (7) or as a set of interconnected channels (7).

FIG. 5 is an axial cross section through a second embodiment of the closure device not in-place on the container. In this second embodiment the perforations (12) and the channels (13) are aligned to form smooth tunnels which bore through the circular ledge (14) and the deformable and elastic structure (15). The deformable and elastic structure (15), for example made from silicon rubber, in this embodiment has the shape of a thick cylindrical ring positioned between the ledge (14) and the cap wall (16). This elastic and deformable structure (15) is perforated at regular intervals to form the channels (13) which are aligned to the perforations (12) in the rigid plate (17). Therefore, in this embodiment each perforation (12) is connected to one channel (13). The benefit of such an alignment is a reduction in dead-space volume when liquid flows from the reservoir (19) to the porous structure (18). In this second embodiment, a tube with a one way pressure valve (20) is provided in the cap wall (16) which allows gas (e.g. air) to enter the reservoir (19) from outside in case of under-pressure in the reservoir.

FIG. 6 shows the cap according to FIG. 5 screwed onto the neck of the container thereby closing it. When the closure device is in-place on the neck of the container, the deformable and elastic structure (15) is deformed by the container mouth (21) having come in close proximity with the rigid plate (17) and closes-off the channels. Said closure stops the flow of liquid from the reservoir (19) into the porous structure (18). The dispensed liquid which may be present in the porous structure (18) may suitably evaporate and/or drip into the interior of the container.

Both the first and second embodiment of the closure device as illustrated in FIG. 1 to FIG. 4 and FIG. 5 and FIG. 6 respectively comprise a circular ledge (9, 14). The ledge (9, 14) provides added structural stability, allows improved control over the shape of the deformable and elastic structure (10, 15) when deformed and may improve restriction of the flow of liquid (i.e. reduces leakage) by the compressed deformable and elastic structure. Although not essential preferably the closure device according to the invention comprises a ledge (9, 14).

The reservoir (5, 19) in the closure device is a hollow formed by the cap wall (3, 16) and the rigid plate (4, 17). Preferably the reservoir (5, 19) comprises an absorbent material and more preferably comprises a material with an open cell structure, a sponge-like structure or a low-density fibre structure or combinations thereof. Examples of low-density fibre structures are a piece of cotton and a piece of cloth. The presence of absorbent material in the reservoir (5, 19) controls the flow-rate of liquid from the reservoir to the porous structure (8, 18). Preferably said open cell, sponge-like and/or low-density fibre structures comprise, more preferably are essentially made of, polymers and/or natural polymers, even more preferably comprise, still even more preferably are essentially made of, compounds selected from the list consisting of polypropylene, polyurethane, polyvinyl, polysulphone, polymers of starch, cellulose, agarose, casein, chitosan or lactic acid and combinations thereof.

The rigid plate (4, 17) is preferably not adjustable in relation to the cap wall (3, 16) (e.g. is fixed to the cap wall), more preferably both the cap wall and the rigid plate are made from a rigid material and even more preferably comprise or essentially consist of hard metal and/or hard polymer (e.g. a hard plastic at room temperature). The rigid plate (4, 17) comprises one or more perforations (6, 12) capable of allowing liquid to transfer from the reservoir (5, 19) to the porous structure (8, 18) via the one or more channels (7, 13). Depending on the specific use and application of the closure device the size of the perforations (6, 12) and the size of the channels (7, 13) may vary. It will be appreciated that the width of the one or more perforations (6, 12) and the connecting channels (7, 13) should be such as to be capable of allowing fluid to flow from the reservoir (5, 19) to the porous structure (8, 18), such as by capillary force and/or gravity (when the closure device is not in place and the container is open). Preferably the average diameter of the perforations in the rigid plate (4, 17) ranges from 0.05 to 8 millimetre, more preferably from 0.1 to 5 millimetre, even more preferably from 0.25 to 4 millimetre and still more preferably from 0.5 to 2 millimetre. Preferably the average length of the flow passage from the reservoir (5, 19) to the porous structure (8, 18) ranges from 0.01 to 50 millimetre, more preferably from 0.1 to 40 millimetre, even more preferably from 1 to 30 millimetre and still more preferably from 3 to 15 millimetre. With perforation (6, 12) is indicated the position where liquid may pass through the rigid plate (4, 17). A perforation (6, 12) connected to a channel (7, 13) forms an end of said channel. For example, in case of a thick rigid plate (4, 17), the tunnel through said plate may also be considered as part of a channel (7, 13).

Liquid material flowing from the reservoir (5, 19) into the porous structure (8, 18) will pass at least one perforation (6, 12) and at least one connecting channel (7, 13). Multiple channels (7, 13) may connect to the same perforation (6, 12), one channel may connect to all the perforations (e.g. as in the embodiment illustrated in FIG. 1 to FIG. 4) and each perforation may connect to one channel (e.g. as in the embodiment illustrated in FIG. 5 to FIG. 6). The channels (7, 13) may be simple or branched. A characteristic feature of the closure device according to the invention is that at least one, preferably all said channels (7, 13) are at least partly formed by a deformable and elastic structure (10, 15) which allows the flow through the channel to be restricted when said structure (10, 15) is deformed. Although the term ‘channel’ (7, 13) is used the channels need not have any particular shape and/or length as long as they allow flow of liquid from the reservoir (5, 19) to the porous structure (8, 18), preferably by a combination of capillary forces and gravity, more preferably by capillary force, when the closure device is not in-place on the container (container is opened).

The number of perforations (6, 12) and channels (7, 13) may affect the overall flow-rate of liquid from the reservoir (5, 19) into the porous structure (8, 18) (when the closure device is not in place on the container). It will be appreciated that the number of perforations (6, 12) will typically also relate to the size of the cap (i.e. a rigid plate (4, 17) with a large surface area typically contains a larger number of perforations). Preferably the number of perforations (6, 12) in the rigid plate (4, 17) is 2 to 100, more preferably 2 to 25, even more preferably 3 to 15 and still even more preferably 5 to 12. Preferably the number of communicating channels (7, 13) equals the number of perforations (6, 12) to allow separate flow-streams of liquid from the reservoir (5, 19) to the porous structure (8, 18). Preferably the channels (7, 13) are spaced as to allow liquid to enter (i.e. be absorbed by) the porous structure (8, 18) at different points.

Preferably the perforations (6, 12) are spaced (as shown in FIG. 4) as to allow liquid to exit the reservoir (5, 19) at different points. It will be appreciated that depending on the specific design and application of the closure device there is a maximum flow-rate of liquid from the reservoir (5, 19) to the porous structure (8, 18) and a minimum time required to saturate the porous structure. Preferably the time between opening and closing a container with a container device according the invention is 1 to 1200 seconds, more preferably 5 to 600 seconds and even more preferably 15 to 240 seconds.

The saturation level of the porous structure (8, 18) enables a metered amount of dispensed liquid to be exposed to the interior of the container. When fully de-saturated preferably the porous structure (8, 18) is capable of absorbing 0.1 to 50 volume percent, more preferably 0.5 to 25 volume percent, even more preferably 0.75 to 15 volume percent and still more preferably 1 to 5 volume percent of the maximum volume of the liquid with which the reservoir (5, 19) can be filled. In case the reservoir (5, 19) of the closure device according to the invention is completely filled with liquid, preferably the closure device is capable of dispensing a metered amount of liquid for 2 to 50, more preferably 3 to 25, even more preferably 4 to 12 and still more preferably 5 to 8 closing actions. It will be appreciated that these closing actions preferably are not performed in quick succession to suitably allow at least part of the liquid present in the porous structure (8, 18) to evaporate when the container is closed with the closure device. It will be appreciated that depending on the specific embodiment of the closure device and the specific application (e.g. type of liquid) the time required to release a metered amount from the porous structure (8, 18), when in-place on the container, may vary. To provide a successive metered liquid dispensing action, the closure device according to the invention preferably is left in place on the container for 1 to 7200 minutes, more preferably 10 25 to 3600 minutes, even more preferably 30 to 600 minutes and still more preferably 60 to 120 minutes.

Any structure which is capable of being impregnated with the dispensed liquid and which may preferably allow evaporation of at least part of the retained liquid may suitably form the porous structure (8, 18). Preferably the porous structure (8, 18) is absorbent. An absorbent porous structure (8, 18) may increase the flow-rate of liquid from the reservoir (5, 19) when the closure device is not in-place on the container. Preferably the porous structure (8, 18) comprises an absorbent material with an open cell structure, a sponge-like structure or a low-density fibre structure or combinations thereof; which may be impregnated by the dispensed liquid and positioned to be in contact with the interior (e.g. headspace) of the container. An example of a low-density fibrous structure is a piece of cotton or a piece of cloth. Preferably said absorbent material comprises, more preferably is essentially made of, polymers and/or natural polymers, even more preferably comprises, still even more preferably is essentially made of, compounds selected from the list consisting of polypropylene, polyurethane, polyvinyl, polysulphone, polymers of starch, cellulose, agarose, casein, chitosan or lactic acid and combinations thereof. It will be appreciated that preferably the liquid attraction (e.g. capillary force), if any, of the reservoir (5, 19) is lower than that of the porous structure (8, 18) and allows liquid to move from the reservoir into the porous structure via the one or more perforations (6, 12) and channels (7, 13).

The surface of the rigid plate (4, 17), facing the container interior when the closure device is in closed position, may form microstructures which are connected to the channels (7, 13) and capable of being impregnated (e.g. absorbing) liquid from the channels by capillary forces. Examples of such microstructures are grooves etched into the surface of the rigid plate (4, 17) and in line with a channel (7, 13). Such microstructures thus may form a porous structure (8, 18) and fall within the ambit of the present invention.

Liquid may be released from the porous structure (8, 18) into the container by dripping (i.e. as droplets). As such it may effectively be dosed onto the surface of the container contents. Liquid present in the porous structure (8, 18) may leave the structure as a gas, for example by evaporation. As a gas the dispensed material may efficiently distribute over the entire air-exposed surface of the container (e.g. headspace, the interior face of the container walls as well as its contents). Liquid present in the porous structure (8, 18) may also leave the structure by a combination of dripping and evaporation. A combination of dripping and evaporation enables distribution of the dispensed material over the entire air-exposed surface of the container but with a relatively high concentration dispensed onto the surface of the container contents (e.g. a food).

Dripping of dispensed liquid directly onto the container contents may lead to a high local concentration (e.g. on the surface), off-taste and/or a reduced overall effectiveness of the dispensed material (e.g. preservative). Preferably at least part of the dispensed liquid and more preferably all the dispensed liquid leaves the porous structure (8, 18) by evaporation (i.e. as a gas). Evaporated liquid more efficiently distributes over the entire air-exposed surface of the container and its contents.

When not in place on the container, liquid may enter the porous structure (8, 18) until a point of saturation of the porous structure is reached. After this point the flow-rate of the liquid will drop (e.g. a reduced flow may still continue driven by evaporation of liquid from the porous structure (8, 18) and/or by dripping). Preferably the absorbent capacity (i.e. capacity to hold liquid) of the porous structure (8, 18) and the type of liquid are suitable chosen to minimize liquid lost due to dripping when the closure device is not in place on the container. It will be appreciated that a volume of liquid flowing out of the reservoir (5, 19) may require a similar volume of air to enter into the reservoir to avoid formation of an under-pressure. Suitably air may enter move up the one or more channels (7, 13) and through the one or more perforations (6, 12) to relieve the under-pressure in the reservoir (5, 19). Preferably a closure device according to the invention may be fitted with one or more openings (20) (e.g. tubes) through the cap-wall (3, 16), more preferably above the level of the liquid in the reservoir (5, 19) (e.g. the top part of the cap wall) which even more preferably comprise one-way pressure operated valves to enable air to enter the reservoir (5, 19) in case of under-pressure. Said one-way valve also prevents evaporation of liquid in the reservoir along the said one or more openings (20) in the cap wall. Reducing under-pressure, if any, in the reservoir (5, 19) may improve the flow-rate of liquid from the reservoir into the porous structure (8, 18) when the cap is not in-place on the container.

It will be appreciated that typically dispensed material moves from the porous structure (8, 18) into the headspace of the container. The term headspace generally indicates the region of the interior of the container above the level of any product contained therein. It will be appreciated that this term also encompasses the situation where what is defined as the headspace is a closed void formed beneath the closure cap. Preferably gas emanating from the porous structure (8, 18) is capable of contacting the contents of the container.

Upon closure of a container with the closure device according to the invention the deformable and elastic structure (10, 15) is deformed and restricts, preferably completely stops, the flow of liquid going from the reservoir (5, 19) to the porous structure (8, 18) by partly or completely blocking the channels (7, 13). It will be appreciated that typically the force of deformation (e.g. compression) is provided by the muscle power of a consumer who closes the container with the closure device. The parts of the closure device are suitably arranged as to allow the deformable and elastic structure (10, 15) to be deformed (e.g. compressed, squeezed) between the rigid plate (4, 17) and any suitable rigid surface of the container upon closing, such as the rim of the container mouth (11, 21). Preferably the position of the deformable and elastic structure (10, 15) is such that it abuts the rim of the container mouth (11, 21) when the closure device is in place on the container.

Preferably the elastic structure (10, 15) and/or the rigid plate (4, 17) are capable of providing an air-tight seal with the mouth (11, 21) of the container opening. For example, the surface of the rigid plate (4, 17) and/or deformable and elastic structure (10, 15) which abuts the container mouth (11, 21) when the closure device is in place may be coated by a rubber and/or silicon layer.

It will be appreciated that upon opening of the container (e.g. the closure device is removed from the jar by a consumer, i.e. the closure device is not in place on the container) the deformable and elastic structure (10, 15) is capable of reforming to its non deformed (e.g. non compressed) shape and allows unrestricted flow of liquid from the reservoir (5, 19) into the porous structure (8, 18) to resume. Preferably the deformable and elastic structure (10, 15) is capable of substantially re-attaining its uncompressed shape (i.e. allows flow to resume) in a short time-span and preferably within 60 seconds, more preferably within 30 seconds, even more preferably within 15 second and still even more preferably within 5 seconds upon opening of the container. The elasticity of the deformable and elastic structure (10, 15) may be due to any material and/or structure comprised by it. Examples of elastic materials are many types of rubber and examples of elastic structures are coiled spring structures. The deformable and elastic structure (10, 15) preferably comprises (or essentially consists of) elastomers and more preferably comprises (or essentially consists) of one or more compounds selected from the list consisting of silicon rubber, natural rubber, nitrile rubber, hydrogenated nitrile rubber, ethylene propylene rubber, polyurethane and fluoroelastomers.

It was found that the closure cap according to the invention is especially suitable for dispensing liquids with a low viscosity. Preferably the viscosity of the liquid is 0.01 to 1000 mPa.s, more preferably 0.1 to 10 mPa.s, even more preferably 0.2 to 5 mPa.s and still even more preferably 0.5 to 1.5 mPa.s at a temperature ranging from 2 to 40 degrees Celsius, and more preferably at a temperature ranging from 15 to 30 degrees Celsius.

The enclosure device is capable of dispensing a metered amount of liquid from the reservoir (5, 19) into the container (via the porous structure (8, 18)). The liquid is transferred from the reservoir (5, 19) to the porous structure (8, 18) when the closure device is not in place on the container (e.g. container is opened). A metered amount of liquid is defined as an amount falling within a chosen minimum and maximum amount. Subject to considerations such as the specific application of the closing device, the volume of container, the volume of the reservoir (5, 19), the concentration of an active in the liquid and the desired number of dispensing actions; the minimum and maximum volume chosen to form the metered amount of liquid may vary. Preferably a metered amount is 0.1 to 50 vol. %, more preferably 0.5 to 25 vol. %, even more preferably 0.75 to 15 vol. % and still more preferably 1 to 5 vol. % of the volume of the liquid with which the closure device is initially loaded.

Preferably the ratio of the volume of the reservoir (5, 19) to the volume of the container is 0.001:1 to 1:1, more preferably 0.01:1 to 2:1, even more preferably 0.05:1 to 3:1 and still even more preferably is 0.1:1 to 5:1.

It will be appreciated that preferably before the container is opened for the first time by the consumer, the reservoir (5, 19) of the closure device is filled as far as possible with liquid material to be dispensed. Also encompassed are embodiments of the closure device which allow refilling of the reservoir (5, 19) with liquid material. The maximum volume of liquid with which the reservoir (5, 19) may be filled depends on the structure of the reservoir, such as the density of the reservoir. Preferably the reservoir (5, 19) is filled with 10 to 95 volume percent, more preferably 20 to 80 volume percent, even more preferably 30 to 70 volume percent and still more preferably 30 to 60 volume percent of liquid based on the total volume of the reservoir.

The liquid which may be present in the reservoir (5, 19) may have any suitable chemical property and for example form a watery or oily solution. For example, the liquid may be an organic and/or inorganic solvent or comprises a mixture of solvents. Preferably the liquid is a volatile material to allow efficient transformation of the dispensed liquid into gaseous form in the porous structure (8, 18). It will be appreciated that preferably the liquid does not compromise the structural integrity of the closure device, for example by dissolving the structural components of the reservoir (5, 19). The liquid may be a mixture of liquids.

Preferably the reservoir (5, 19) comprises a liquid and more preferably a liquid which is a Newtonian fluid and even more preferably a liquid which is a water-continuous system. Preferably the liquid comprises one or more actives selected from the list consisting of dietary supplements, antioxidants, flavours, colouring agents, preservatives, thickeners, surfactants, dispersing agents, release agents, diffusing agents and stabilisers, more preferably one or more antimicrobials and even more preferably bacteriocides or fungicides and combinations thereof. Preferably the liquid comprises compounds selected from the list consisting of lactic acid, acetic acid, peracetic acid, tartaric acid, benzoic acid, sodium and potassium sulphites, sodium and potassium nitrites, sodium and potassium bicarbonate, sodium and potassium sorbates, sodium and potassium benzoates, hydroxyl-8 quinoline, peroxide, salts, ethanol, sodium hypochlorite, nisin and other bacteriocins and combinations thereof. The liquid may essentially consist of said compounds in case these are liquid themselves. The actives may be dissolved in the liquid according to the standard way in accordance with the chosen ingredients. It will be further appreciated that based on the specific properties of the liquid, liquid is dispensed into the porous structure (8, 18) and may completely evaporate. Preferably when the liquid and/or any compounds present in the liquid leave a residue when the liquid evaporates (e.g. salts) preferably these kinds of liquids at least partly drip through the porous structure (8, 18) in liquid form.

USE

A closure device according to the invention is capable of dispensing a metered amount of liquid, such as a preservative (i.e. a liquid which comprises a preservative and/or is a preservative itself). This allows the areas of the container and the contents therein which have been exposed, for example to the air (e.g. surface of a sauce such as a mayonnaise) to be treated with preservative (by dripping and/or evaporation of the dispensed liquid from the porous structure). Furthermore, the container interior and its contents may be treated with dispensed material upon more than one closing actions. The dispensed material may contact the contents of the container in the form of liquid, but preferably at least partly and more preferably essentially completely in gaseous form. Said transformation may suitably occur in the porous structure (8, 18) (e.g. by evaporation). Therefore, by virtue of allowing treatment and re-treatment of the air-exposed area with a preservative the open shelf-life of the container contents may be extended. Accordingly the present invention encompasses a method to extend the open shelf-life of spoilage sensitive contents, such as food, held in a container by closing the container with a closure device according to the invention wherein the reservoir (5, 19) comprises a preservative.

A feature of the closure device according to the invention is that the dispensing of liquid into the porous structure (8, 18) may occur relatively quickly, while the dripping and/or evaporation from the porous structure may occur relatively slowly (depending on the nature of the liquid). This feature makes the closure device especially suitable for food containers which are opened and closed in quick succession to control the amount of liquid dispensed in a short amount of time. For example during dinner, a mayonnaise jar may be opened and closed several times while only a small amount of mayonnaise may be consumed each time. In such a case, the porous structure (8, 18) may reach saturation during the first opening after which little liquid from the reservoir (5, 19) is further dispensed. Subsequently when, for example after dinner, the container is stored, for example in the cupboard or refrigerator, the porous structure (8, 18) can suitably release the metered dispensed liquid by evaporation and/or dripping. As such the device may more effectively be used to extend the shelf-life of foods as it may allow dispensing of liquid, such as a preservative, over a greater part of the product's life-time (i.e. the time span between the first opening of the container by the consumer and the time at which the product is essentially consumed). Accordingly a method is encompassed by the present invention to extend the open-shelf life of products, for example dinner supplements, held in a container by closing the container by a closure device according to the invention, wherein their use typically involves periods of opening/closing the container in quick succession.

In more traditional methods to extend the open shelf-life of foods, preservatives (i.e. chemical preservatives) may be completely mixed throughout the food product during manufacture. Mixing of a relatively large amount of preservatives is required since it is not know beforehand which parts of the product will be directly exposed (e.g. surface layer) during use and which parts will not (e.g. parts of the mayonnaise in the bottom corner of a jar). By use of the closure device according to the invention, preservatives are added to the area of the container and its contents which have been directly exposed to the air (e.g. the surface).

Therefore a lower amount of total preservatives may be required to provide an extended open shelf-life. The present invention encompasses a method to reduce the amount of required preservative to provide a suitable open shelf-life of spoilage-sensitive product by closing the container by a closure device according to the invention. It will be appreciated that in a method according to the invention to reduce the amount of chemical preservatives preferably, during manufacturing the contents will have undergone one or more suitable physical preservation processes such as, heating, irradiation, drying and/or freezing.

Preferably the method according to the invention to extend the open shelf-life and/or reduce the amount of preservative are applied to a container comprising an edible product comprising 5 to 95 weight percent of water, more preferably an edible product selected from the list consisting of sauces, purees, candied fruits, jams, cooked vegetables, compotes, water-in-oil emulsions, oil-in-water emulsions, pastes, creams, dairy products and food concentrates and combinations thereof and even more preferably comprises an edible product selected from the list consisting of dairy based spreads, low-fat margarines, margarines, preservative free margarines, mayonnaise, dressings, puddings, tomato sauce, beverages such as teas and milk teas, condiments such as pesto sauce, jelly-based soup-, gravy- and sauce concentrates and combinations thereof. 

1. A container closure device capable of dispensing a metered amount of a liquid into a container, wherein said container cap comprises: a cap wall (3), a reservoir (5) capable of being filled with liquid, a porous structure (8), a rigid plate (4) positioned between said reservoir and said porous structure (8), wherein said plate comprises one or more perforations (6) communicating with said reservoir (5), and one or more channels (7) capable of communicating said perforation (6) with the porous structure (8), wherein at least part of said one or more channels (7) is formed by a deformable and elastic structure (10) capable of limiting communication through said channels (7) upon deformation.
 2. A closure device according to claim 1, wherein the average diameter of the perforations (6) in the rigid plate (4) ranges from 0.1 to 5 millimetre and preferably from 0.5 to 2 millimetre.
 3. A closure device according to claim 1, wherein the number of perforations (6) is 2 to 25 and preferably 5 to
 12. 4. A closure device according to claim 1 wherein the porous structure (8) is capable of absorbing 0.5 to 25 volume percent and preferably 1 to 5 volume percent of the maximum volume of the liquid with which the reservoir (5) can be filled.
 5. A closure device according to claim 1 wherein the closure device is capable of dispensing a metered amount of liquid for 2 to 50 and preferably 5 to 8 closing actions.
 6. A closure device according to claim 1 wherein the porous structure (8) comprises an absorbent material and more preferably comprises a material with an open cell structure, a sponge-like structure or a low-density fibre structure or combinations thereof.
 7. A closure device according to claim 1 wherein the deformable and elastic structure (10) is capable of attaining its uncompressed shape preferably within 60 seconds and more preferably within 5 seconds upon opening of the container.
 8. A closure device according to claim 1 wherein the deformable and elastic structure (10) comprises one or more compounds selected from the list consisting of silicon rubber, natural rubber, nitrile rubber, hydrogenated nitrile rubber, ethylene propylene rubber, polyurethane and fluoroelastomers.
 9. A closure device according to claims 1 to 8, wherein the reservoir (5) comprises a liquid with a viscosity of 0.1 to 10 mPa.s, preferably 0.5 to 1.5 mPa.s, at a temperature ranging from 2 to 40 degrees Celsius.
 10. A closure device according to claim 1 wherein the reservoir (5) comprises a liquid comprising one or more actives selected from the list consisting of dietary supplements, antioxidants, flavours, colouring agents, preservatives, thickeners, surfactants, dispersing agents, release agents, diffusing agents and stabilisers and more preferably one or more antimicrobials.
 11. A closure device according to claim 1 wherein the reservoir (5) comprises a liquid comprising compounds selected from the list consisting of lactic acid, acetic acid, peracetic acid, tartaric acid, benzoic acid, sodium and potassium sulphites, sodium and potassium nitrites, sodium and potassium bicarbonate, sodium and potassium sorbates, sodium and potassium benzoates, hydroxyl-8 quinoline, peroxide, salts, ethanol, sodium hypochlorite, nisin and other bacteriocins; and combinations thereof.
 12. A container fitted with a closure device according to claim 1 wherein the ratio of the volume of the reservoir (5) to the volume of the container ranges from 0.001:1 to 1:1, preferably from 0.1:1 to 5:1.
 13. Method to extend the open shelf-life of spoilage-sensitive contents held by a container comprising the step of closing the container with a closure device according to claim 1 wherein the reservoir (5) comprises a preservative.
 14. Method according to claim 13, wherein said spoilage-sensitive contents comprise an edible product selected from the list consisting of dairy based spreads, low-fat margarines, margarines, preservative free margarines, mayonnaise, dressings, puddings, tomato sauce, beverages such as teas and milk teas, condiments such as pesto sauce, jelly-based soup-, gravy- and sauce concentrates and combinations thereof.
 15. Method according to claim 13 wherein at least part of the liquid dispensed into the porous structure (8), and more preferably all the dispensed liquid, is transformed into a gas before coming into contact with the contents of the container. 